haskell-template now has dedicated documentation

[srid]

https://srid.ca/haskell-template

I hope to document "how to do X" kind of things here.

[billksun]

I guess as a first "how to" question from a beginner:
How do I specify a GHC version to use?

[srid]

Good idea; noted in #41

[subterfugue]

How would someone add a dependency in the flake, non-haskell related?

[srid]

Example: emanote adds stork as both build-time (comes from here) and runtime dependency.

[subterfugue]

Interesting, that project has weird ways to define hls and ghcid, they're done differently in this generic template.

[srid]

Are you referring to the use of attrsets instead of lists? The buildTools option come from https://github.com/srid/haskell-flake and it was @roberth 's suggestion originally to go with attrsets (because you can then override the defaults on a per-dependency basis; as Emanote demonstrates with ghcid, etc. all). TBH, I don't know of better ways to do it.

[srid]

Also: https://haskell.flake.page/

[subterfugue]

I find the adding a package from Nixpkgs into the flake something that I do frequently and there should be an option to do this easily (and especially documentation for this, which is why i posted this here... add a "how to add an input" option?), because otherwise it seems rather confusing and error-prone to me. I have https://termpad.com/UglyDifficultZebra
which is erroring because

error: attribute 'llvm' missing

       at /nix/store/4w4df1qqjxy58xyzxszk47gnlmdpg5d2-source/flake.nix:33:26:

           32|           devShell = {
           33|             tools = hp: {
             |                          ^
           34|               treefmt = config.treefmt.build.wrapper;
(use '--show-trace' to show detailed location information)

I tried to use inherit (config.packages.llvmPackages_15) llvm; first because that's the version i actually want, but as a last resort tried the above and it failed. I'm not quite sure what I'm doing wrong.

[srid]

@ribosomerocker Why are you using config.packages?

[subterfugue]

Because that's what I've see being used in the links you posted 😅

[srid]

inherit (config.packages) llvm;

This should be:

inherit (pkgs) llvm;

config.packages refers to the packages in your local flake which obviously doesn't export llvm.